Helically shaped electrophysiology catheter

ABSTRACT

An electrophysiology (EP) device suitable for ablating tissue within a patient&#39;s body lumen. The EP device of the invention generally comprises an elongated shaft having a distal shaft section with a helical shape and at least one electrode on an exterior portion thereof. One aspect of the invention comprises a method of performing a medical procedure, such as treating a patient for atrial arrhythmia, by forming a lesion using an EP device embodying features of the invention.

BACKGROUND OF THE INVENTION

This invention generally relates to the treatment of cardiac arrhythmiaand particularly atrial fibrillation and atrial flutter.

Atrial fibrillation is the disorganized depolarization of a patient'satrium with little or no effective atrial contraction. Prior methods fortreating a patient's arrhythmia include the use of anti-arrhythmic drugssuch as sodium and calcium channel blockers or drugs which reduce theBeta-adrenergic activity. Other methods include surgically sectioningthe origin of the signals causing the arrhythmia or the conductingpathway for such signals. However, the surgical technique is quitetraumatic and is unacceptable to a large number of patients. A morefrequently used technique to terminate the arrhythmia involvesdestroying the heart tissue which causes the arrhythmia by ablativeenergy, e.g., applying a laser beam or high frequency electrical energysuch as RF or microwave energy, to a desired arrhythmogenic site orpathway on the patient's endocardium. In the latter method,intravascular electrophysiological (EP) devices can be used to formlesions within a patient's atrial chamber to provide results similar tothe surgical segregation techniques in terminating atrial fibrillation,but with significantly reduced trauma.

Typically, the EP device is advanced within a patient's vasculature andinto a heart chamber, and a lesion is formed on the endocardium when RFelectrical energy is emitted from electrodes of the device. RF ablationtechniques produce lesions of a small area, so that several lesions aretypically formed to completely ablate an area. A major problem of RFablation techniques is forming a lesion of the requisite size, whichcompletely ablates the area of interest but does not unnecessarilydestroy surrounding healthy tissue.

What has been needed is an ablation device which allows for improvedcreation of lesions of a requisite shape. The present inventionsatisfies these and other needs.

SUMMARY OF THE INVENTION

This invention is directed to an electrophysiology (EP) device forablating tissue within a patient's body lumen. The EP device of theinvention generally comprises an elongated shaft having a distal shaftsection with a helical shape and at least one electrode on an exteriorportion thereof. One aspect of the invention comprises a method ofperforming a medical procedure, such as treating a patient for atrialarrhythmia, by forming a lesion using an EP device embodying features ofthe invention. The terminology helically shaped should be understood torefer to at least one turn having a distal portion of the turnlongitudinally spaced from a proximal portion of the turn, at least whenthe helically shaped section is not in a reversibly stacked,longitudinally collapsed configuration.

In one embodiment, the helical shape of the distal shaft section isconfigured to conform to the inner diameter of a patient's body lumen,to form one or more lesions which extend around a wall defining the bodylumen. Thus, the turns of the helical distal shaft section have an outerdiameter which is not significantly smaller or significantly larger thanthe inner diameter of the body lumen at the desired site of the lesion.In a presently preferred embodiment, the diameter of the turns issubstantially equal to the inner diameter of the body lumen, so that theturns contact the wall defining the body lumen without significantlyexpanding and injuring the body lumen wall.

In another embodiment, the distal shaft section has a proximal portionwith a helical shape and a distal portion with a noncoiled shape, and atleast one electrode on the distal shaft section. The noncoiled distalportion, which thus is not wound into circular or helically spiraledconfiguration, in one presently preferred embodiment has a substantiallystraight shape. The terminology “substantially straight” should beunderstood to mean a portion configured to extend in a line, althoughsome minor variations in the shape of the portion may be present. In apresently preferred embodiment, electrodes for ablation, and optionallyalso for sensing and pacing, are on the helical proximal portion. In oneembodiment, electrodes for sensing and/or pacing are provided on thenoncoiled distal portion of the distal shaft section, which can be usedto map electrical activity in the region of the electrodes, or to pacethe electrical activity of a region of the patient's anatomy such as thepatient's heart.

In a presently preferred embodiment, the EP device has a core memberextending within the elongated shaft. The core member preferably has ahelically shaped distal section to provide the helical shape to thedistal shaft section of the EP catheter. The core member may be fixedwithin the shaft, or alternatively, slidably disposed therein. In theembodiment in which the core member is slidably disposed within theshaft, a variety of different core members may be provided allowing thephysician to choose a core member comprising a particularly suitablesize, shape or material. Thus, an EP device with a distal shaft sectionhaving a desired shape is provided by inserting a core member having thedesired shape therein. The core member may be provided with one or morejackets, which may be electrically insulating, having a total thicknessof preferably less than about 0.001 inch (0.025 mm).

The distal shaft section of the EP device is preferably reversiblydeformable from the helically shaped configuration to a lower profileconfiguration for advancement within the patient's vasculature. In oneembodiment, the EP device of the invention is slidably disposed in thelumen of a guiding catheter, so that the radial force of the guidingcatheter against the device reversibly collapses the turns of thehelically shaped distal section to smaller diameter turns which fitwithin the guiding catheter. In another embodiment, the turns of thehelically shaped distal section are configured to reversibly collapsecompletely, so that the guiding catheter straightens the helicallyshaped distal section to a straight configuration. The EP device distalshaft section is thus constrained from assuming the expanded helicalconfiguration until the device is displaced out a distal end of theguiding catheter.

The one or more electrodes on the helically shaped distal shaft sectioncan be used as ablation electrodes to form a lesion from within apatient's body lumen when electrical energy, and preferably highfrequency energy such as RF energy, is emitted therefrom. The ablationelectrode(s) on the helically shaped distal shaft section may be acombination ablation and sensing electrode, which is capable of ablationand detection of electrical activity from within a lumen of thepatient's body. In a presently preferred embodiment, the ablationelectrode on the helically shaped distal shaft section is a helical coilfor improved device flexibility, although other electrode designs aresuitable including cylindrical bands, arcuate bands, ribbons or thelike. A temperature sensor such as a thermocouple may be provided on theEP device. In one embodiment, the device includes one or more electrodesfor mapping and/or pacing are provides on the shaft proximal and/ordistal to the helically shaped section in addition to the electrodes onthe helically shaped section. Preferably, the electrodes on thehelically shaped distal shaft section are configured for unipolar useduring ablation, and bipolar use during sensing, by use of amultiplexing switchbox. The sensing/pacing electrodes proximal and/ordistal to the helically shaped section are preferably configured forbipolar use, but may be configured for unipolar mode use. In theunipolar sensing/pacing mode, a separate, return electrode which is noton the EP device shaft but which is in contact with the exterior surfaceof the patient's body is used.

In a method of the invention, the helically shaped distal shaft sectionof the EP device is placed at an ostium or within a body lumen at adesired location. The terminology “body lumen” should be understood toinclude a variety of structures in the body, including a blood vesseland a heart chamber. Typically, an EP device assembly comprising the EPdevice of the invention within a guiding catheter is advanced within apatient's body lumen to a desired location therein. The EP device distalshaft section is then deformed from the low profile configuration to thehelical configuration by displacing the EP device relative to theguiding catheter so that the distal shaft section of the device extendsat least in part outside of the guiding catheter lumen in the bodylumen. The helically shaped distal shaft section of the device contactsa wall defining the body lumen or ostium. The electrodes are then usedto detect electrical activity from within the body lumen to determinethe desired site for forming a lesion. One or more of the electrodes onthe helically shaped distal shaft section contact the wall defining theostium or the inner surface of the body lumen, so that delivery of highfrequency energy to the electrodes forms a lesion extending in whole orin part, one or more times, around the ostium or the inner surface ofthe body lumen. The lesion may be a helically shaped lesion extendingspirally along a length of the body lumen, or may be one or morecircular lesions. The helical shape of the distal shaft section isconfigured to provide lesions particularly suitable for treatment ofatrial arrhythmia including atrial fibrillation or flutter. In oneembodiment, a plurality of discontinuous lesions are formed, which thuslimits or avoids the possible disadvantageous results, such as stenosisformation and spasms in the ablated region, which otherwise occur from acontinuous lesion extending around the full circumference of the ostiumor body lumen.

The EP device of the invention provides for improved lesion formationdue to the ablation electrodes on the helically shaped distal sectionhaving at least one 360° turn. The helically shaped distal sectionallows for the formation of lesions extending in whole or in part aroundthe inner surface of a patient's body lumen. The turns of the helicallyshaped distal shaft section can be moved closer together or furtherapart within the patient to provide the desired lesion pattern.Additionally, the device has a low profile configuration for advancementwithin the patient which self expands into the helically shapedconfiguration for easy of deployment within the patient. These and otheradvantages of the invention will become more apparent from the followingdetailed description and the accompanying exemplary drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of an EP device embodying features of theinvention, having a helically shaped distal shaft section.

FIG. 2 is a transverse cross-sectional view of the EP device shown inFIG. 1, taken along the lines 2-2.

FIG. 3 is an elevational view, partially in section, of an EP deviceassembly embodying features of the invention, illustrating an EP devicein a low profile configuration within a guiding catheter.

FIG. 4 is an enlarged longitudinal cross-sectional view of the EP deviceassembly shown in FIG. 3 taken along the lines 4-4, illustrating the EPdevice distal tip within the guiding catheter.

FIG. 5 is an enlarged longitudinal cross-sectional view of the EP deviceassembly shown in FIG. 3 taken along the lines 5-5, illustrating aportion of the EP device distal shaft section within the guidingcatheter.

FIG. 6 is a transverse cross sectional view of the EP device assemblyshown in FIG. 5, taken along lines 6-6.

FIG. 7 is a transverse cross sectional view of an alternative embodimentof an EP device assembly embodying features of the invention, having acore wire slidably disposed in a lumen in the device shaft.

FIG. 8 is an elevational view, partially in section, of a patient'sheart and an EP device assembly embodying features of the invention,with the distal end of the EP device transeptally positioned within apulmonary vein.

FIG. 9 is an elevational view, partially in section, of the EP deviceassembly of FIG. 8, with the turns of the helically shaped distal shaftsection moved closer together in a stacked configuration.

FIG. 10 is an elevational view of an alternative embodiment of an EPdevice embodying features of the invention comprising a distal shaftsection having a proximal portion with a helical shape and a distalportion with a noncoiled shape with a pair or sensing and/or pacingelectrodes on the distal portion.

FIG. 11 is a longitudinal cross sectional view of the distal end of theEP device of FIG. 10, taken within circle 11.

FIG. 12 is an elevational view, partially in section, of the EP deviceof FIG. 10, positioned in contact with a wall defining a pulmonary veinostium, with the turns of the helically shaped distal shaft sectionmoved closer together in a stacked configuration.

FIG. 13 is an elevational view of an alternative embodiment of an EPdevice embodying features of the invention comprising a distal shaftsection having a proximal portion with a helical shape with one and onequarter turns, and a distal portion with a noncoiled shape.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates one embodiment of the EP device 10 of the invention,generally comprising an elongated shaft 11 having a proximal shaftsection 12, a helically shaped distal shaft section 13, and a pluralityof electrodes 14 on the distal shaft section 13. An electrical connector15 and an adapter 16 are on the proximal end of the device. FIG. 2illustrates a transverse cross section of the distal end of the device10 shown in FIG. 1, taken along lines 2-2.

FIG. 3 illustrates the EP device 10 within a guiding catheter 20 forintroduction and advancement within the patient. The guiding cathetergenerally comprises an elongated shaft 21 having a proximal end 22, adistal end 23, a port 24 in a proximal shaft section, a port 25 in adistal shaft section, and a lumen 26 extending within the shaft to theport in the distal shaft section. As illustrated in FIG. 3, thehelically shaped distal shaft section of the EP device 10 is reversiblydeformed from the helical configuration to a low profile configurationwithin the lumen 26 of the guiding catheter. In the embodimentillustrated in FIG. 3, with the EP device slidably disposed withinguiding catheter lumen 26, the radial force of the guiding catheter 20against the device reversibly straightens the helically shaped distalsection to form a straight configuration. The helically shaped distalshaft section 13 is preferably self expanding, so that the EP device 10can be advanced out the distal end of the guiding catheter 20, or theguiding catheter 20 proximally retracted, causing the distal shaftsection of the EP device to return to the helically shaped configurationillustrated in FIG. 1. In alternative embodiments (not shown), thehelically shaped distal shaft section reversibly collapses to a helicalshape with turns having a smaller outer diameter when the distal shaftsection is within the guiding catheter lumen 26.

In a presently preferred embodiment, the EP device 10 includes a coremember 17 having a helically shaped distal section, disposed within theshaft 11. As best illustrated in FIG. 5, showing a longitudinal crosssection of the of the EP device shown in FIG. 3, taken along lines 5-5,the shaft 11 comprises a tubular member 18 disposed about the coremember 17. The core member 17 extends within the tubular member to thedistal end of the device, and the tubular member 18 is helically shapedby the core member therein. FIG. 6 illustrates a transverse crosssection of the EP device shown in FIG. 5, taken along lines 6-6.

The core member 17 is preferably formed of a superelastic material, suchas a NiTi alloy, or stainless steel, and has a maximum diameter of about0.01 inch (0.25 mm) to about 0.018 inch (0.46 mm). The core member 17,and preferably a distal section thereof, may be tapered as shown in FIG.4, or optionally flattened. In a presently preferred embodiment, thecore member has an insulating coating 30, such as a polyester orpolyimide coating. The coating 30 is preferably about 0.0005 inch(0.0127 mm) thick. In the embodiment illustrated in FIG. 4, coating 30extends distally to a point distal to the shaft 11 distal end andproximal to the distal end of core member 17. In the embodimentillustrated in FIGS. 5 and 6, the coating 30 on the core member 17contacts an inner surface of the tubular member 18. The core member 17is secured to the tubular member 18 by applying heat to the device tomelt and fuse the tubular member to the core member coating. However, avariety of suitable means of securing the core member within the tubularmember may be used, such as an adhesive (not shown) between the coremember and the tubular member. In an alternative embodiment of theinvention illustrated in FIG. 7, the core member 17 is slidably disposedwithin and removable from a lumen 19 of the tubular member.

As best illustrated in FIG. 4, a flexible coiled tip 27 is provided onthe distal end of the EP device 10. The tip 27 has a closed distal end,and includes a flexible coil 28 extending beyond the distal end of theshaft 11 enclosed within a soft coating 29 preferably formed of apolymeric material. In the embodiment illustrated in FIG. 4, the tip 27has an open center region for increased flexibility. A presentlypreferred polymeric material for the tip 27 is a fluoropolymer such asTHV available from 3M. In the embodiment illustrated in FIG. 4, the coremember 17 is secured to the distal end of the coil 28, by suitablematerial such as gold-tin solder. In another embodiment of theinvention, the coil 28 may be omitted, and the distal end of the EPdevice preferably provided with a soft tip to minimize traumaticengagement with a blood vessel wall.

In the embodiment illustrated in FIGS. 5 and 6, the electrodes 14comprise helical coils which are electrically connected to insulatedelectrical conductors 31. In a presently preferred embodiment, the EPdevice 10 shaft includes thermocouples 32, connected to temperaturesensor electrical conductors 33 and 34 (i.e., thermocouple wires).Thermocouples are preferably located between adjacent electrodes on anouter surface of the shaft 11, although they may alternatively be atother locations on the EP device as is conventionally known. Aconducting member 35, such as a gold band, covers the thermocouples, anda polymeric jacket 36, preferably formed from THV, covers the conductingmember 35 and insulates the thermocouple 32 from noise (e.g. RF noise)present as a result of the energy sent to the electrodes. In theembodiment illustrated in FIG. 5, the electrical conductors 31 andthermocouple wires 33, 34 are braided within the tubular member 18.However, the electrical conductors 31 and thermocouple wires 33,34 mayhave a variety of suitable configurations, including braided or woundconfigurations different from that shown in FIG. 5 or a nonbraidedconfiguration. In an alternative embodiment (not shown), theindividually insulated electrical conductors may be within the tubularmember lumen 19 or at least in part within an outer jacket of the coremember in the embodiment in which the core member is secured to thetubular member. The proximal ends of the electrical conductors 31 andthermocouple wires 33, 34 are electrically connected to individual pinsof multi-pin connector 15 (FIG. 1) on the proximal end of the shaft.

In a method of treating a patient for atrial fibrillation or flutter,the EP device of the invention is used to form a lesion extending aroundan inner surface of the patient's pulmonary vein. FIG. 8 illustrates anassembly in a patient's heart 40, with the EP device 10 in a pulmonaryvein 41. The device 10 is introduced into the patient's vascular system,e.g. the femoral vein, percutaneously or by way of a cut-down, withinthe guiding catheter 20. The assembly is preferably advanced into theright atrium 42 from the inferior vena cava 43, and positioned in theleft atrium 44 transeptally, as illustrated in FIG. 8. The EP device 10distal section extends out of the port in the distal end of the guidingcatheter, so that the helically shaped distal shaft section of thedevice is positioned within the pulmonary vein 41 of the heart. Thepulmonary vein 41 is mapped using electrodes on the device 10, and if apulmonary vein potential is detected, the electrodes on the distal shaftsection are used to form a lesion(s) extending at least in part aroundthe wall defining the pulmonary vein lumen or in the left atrium justoutside a pulmonary vein ostium. The position of the lesion ispreferably chosen to interrupt the conduction path to the atrium.Alternatively, the lesion may be located to ablate the actual focalorigin in the pulmonary vein.

Typically, RF current is delivered to one or two electrodes to perform afirst ablation and then to adjacent electrodes, one or two electrodes ata time, until an ablation of desired length is obtained in the bodylumen. This reduces the overall power requirements for the assembly. Thetemperature sensors can be used to detect the temperature of the heartwall between the adjacent electrodes, to control the high frequencyenergy and determine when the lesions formed by adjacent electrodesoverlap to form continuous lesions on the wall defining the body lumen.Additionally, feedback of the temperature data can be used to modulatethe power and prevent thrombus in the preferred use, and cooling fluidcan also be used. After the ablation, the electrodes 14 can be employedto detect electrical activity to ensure that the ablation has beeneffective in terminating the fibrillation or flutter. Typically, theprocedure is performed for the left and right, superior and inferiorpulmonary veins.

The EP device of the invention can be used to form a helical lesion, aclosed circular lesion, or a curvilinear segmental (i.e., discontinuous)lesion. For example, in the embodiment illustrated in FIG. 8, a helicallesion on the body lumen wall can be formed by delivering RF energy tothe electrodes which as illustrated are contacting the pulmonary veinwall in a helical array. Typically, the helical lesion is formed toextend continuously along the body lumen wall, wherein the individuallesions formed by the longitudinally adjacent electrodes on the shaftoverlap to produce one continuous lesion. The helical lesion comprises aspiral having a distal end, and a proximal end longitudinally spacedfrom the distal end of the spiral. In an alternative embodiment of theinvention, the lesion formed extends in a closed circle around the bodylumen wall, i.e., a lesion having ends that close together to form acircle. A closed circle lesion can be formed by displacing the devicedistal section to change the electrode position on the body lumen wallafter an initial lesion is formed. For example, in one embodiment of themethod of forming a closed circular lesion, a helically shaped lesion isfirst formed on the body lumen wall, and then the helically shapeddistal shaft section of the EP device is rotated or longitudinallydisplaced proximally or distally, and a second lesion which overlapswith the first lesion is formed, to thereby form at least one closedcircular lesion. Alternatively, as illustrated in FIG. 9, the helicallyshaped distal shaft section of the EP device can be provided withclosely spaced, stacked adjacent turns which facilitate the formation ofa closed circle lesion.

The spacing between adjacent turns of the helically shaped distal shaftsection can be changed by the physician during deployment of the EPdevice within the body lumen. To increase the spacing between thehelical turns of the device, the distal extremity of the EP device isdisplaced out of the distal end of the guiding catheter so that it isplaced in contact with the body lumen wall. The guiding catheter isdisplaced proximally, while a proximal portion of the EP device isdisplaced proximally to stretch the turns of the helically shaped distalshaft section apart, so that the portion of the EP device distal shaftsection that is still inside the guiding catheter is deployed therefromwith the spacing between the turns increased. Similarly the spacingbetween the turns may be decreased by retracting the guiding catheterproximally while a proximal portion of the device is displaced distally,to stack the turns of the helically shaped distal shaft sectiontogether.

FIG. 10 illustrates an alternative embodiment of an EP device 110 whichembodies features of the invention, generally comprising an elongatedshaft 111 having a proximal shaft section 112, a distal shaft section113, and a plurality of electrodes 114 on the distal shaft section 113.An electrical connector 115 is on the proximal end of the device 110.The distal shaft section 113 comprises a proximal portion 116 with ahelical shape having one or more turns, and a distal portion 117extending from the proximal portion with a noncoiled shape. In theembodiment illustrated in FIG. 10, the noncoiled distal portion 117 hasa straight shape with an outer surface aligned or parallel with an outersurface of the proximal shaft section 112. As illustrated in FIG. 10,the noncoiled distal portion 117 has a width about equal to or less thanthe width of the proximal shaft section 112. Thus, the noncoiled distalportion 117 does not have the enlarged outer diameter formed by theturns of the helically shaped proximal portion 116. The electrodes 114on the helically shaped proximal portion preferably comprise coiledelectrodes, and temperature sensors 118 are located between the coiledelectrodes 114, preferably on an outer surface of the shaft, asdiscussed above in relation to the embodiment of FIG. 1. In a presentlypreferred embodiment, each electrode 114 has a length of about 3 toabout 6 mm. Although 5 electrodes 114 are illustrated in FIG. 10, thenumber of electrodes 114 may vary, and in a presently preferredembodiment, about 8 electrodes are provided on EP device 110. A pair ofsensing electrodes 119 for mapping and/or pacing are on the distalportion 117 of the distal shaft section. In an alternative embodiment(not shown) at least a second pair of sensing and pacing and pacingelectrodes 119 may be provided on the shaft proximal to the helicallyshaped proximal portion,116. The sensing and pacing electrodes arepreferably spaced away from the helically coiled section 116, and in oneembodiment are about 1 to about 3 cm, preferably about 1.5 to about 2 cmfrom the helically coiled section. In a presently preferred embodiment,the electrodes 114 on the helically shaped portion 116 are configuredfor unipolar use during ablation, and bipolar use during sensing. Thedistal sensing and pacing electrodes 119 are configured for use abipolar electrodes during sensing and pacing. A flexible coiled tip 120is secured to the distal end of the distal portion 117, to facilitateguiding the EP device to a desired location within the patient. In apresently preferred embodiment, the tip coil 120 is about 1 to about 3cm, most preferably about 2 cm in length, and is formed of a radiopaquemetal such as platinum.

The turns of the helical proximal section 116 are illustrated in arelaxed configuration in FIG. 10. However, the turns of the helicalproximal section 116 can be moved closer together or further apartwithin the patient by urging the proximal end of the catheter distallyor proximally, respectively, with the distal end of the catheter in astabilized position within the patient and as discussed above inrelation to the embodiment of FIG. 1.

Each electrode 114 is spaced apart from one or more adjacent electrodes114 on the shaft 111, i.e., the electrodes 114 extend discontinuouslyalong the shaft. However, depending on the duration and power level usedduring an ablation procedure, the lesion(s) formed by electrodes 114 canbe discontinuous or alternatively, can be joined together and thuscontinuous.

In the embodiment illustrated in FIG. 10, the helical proximal portion116 forms one full 360° loop and half of a second loop. In a presentlypreferred embodiment, about one full 360° loop is provided, although thenumber of loops may vary. Because the proximal portion 116 is helical, aproximal section of the 360° loop is longitudinally spaced apart fromthe distal section thereof which completes the circumference of the loopin the relaxed configuration illustrated in FIG. 10. Consequently, thehelical proximal portion forms at least one open or helical 360° loop inthe relaxed configuration, and the electrodes 114 thereon form an openor helical 360°, discontinuous loop. The circumference of one 360° loopof the helically proximal portion 116 varies depending on the desireduse of the EP device. In a presently preferred embodiment, thecircumference of one 360° loop is about 15 mm to about 40 mm, preferablyabout 15 mm to about 30 mm. Depending on the circumference of the loopand the number and length of the electrodes 114, the electrodes 114 mayor may not extend the length of one or more 360° loops. In a presentlypreferred embodiment, the electrodes 114 extend along the length of atleast one 360° loop of the helical proximal portion 116, so that theelectrodes can be used to form a lesion which extends in a continuous360° loop, or a discontinuous, partial segment of a 360° loop. However,in alternative embodiments, the helical proximal portion 116 has apartial loop of less than 360° (not shown), or the electrode number orlength is sufficiently small such that the electrodes extend along alength of a partial loop of less than 360° on the helical proximalportion. The circumference of the helical section, i.e., the length ofthe helical section if it was stretched out to a straight, nonhelicalshape, is about 5 to about 40 mm, preferably about 5 to about 20 mm.

FIG. 11 illustrates an enlarged, longitudinal cross sectional view ofthe distal end of the device 110, taken within circle 11. As illustratedin FIG. 11, the shaft 111 comprises a tubular member 121, having braidedelectrical conductors 122 in the wall of the tubular member 121, andhaving a core member 123 in a lumen of the tubular member 121. In theembodiment illustrated in FIG. 11, the core member 123 is secured to theflexible coiled tip 120. An outer layer 124 on an outer surface of thetubular member 121 overlaps the ends of the sensing and pacingelectrodes 119.

FIG. 12 illustrates the device 110 with the helically coiled proximalportion 116 of the distal shaft section 113 in position at the ostium 46of a pulmonary artery which forms the junction between the pulmonaryartery and the right atrium of the patient's heart. As illustrated inFIG. 12, the turns of the helically shaped proximal portion 116 are in astacked configuration after having been moved closer together than thenatural relaxed spacing shown in FIG. 10, by distally forcing thecatheter against the wall defining the ostium of the pulmonary artery.As a result, the electrodes 114 extend discontinuously, completelyaround the ostium. High frequency energy is delivered to one or more ofthe electrodes 114 to form a lesion extending at least in part aroundthe ostium. The lesion can be caused to be a continuous or adiscontinuous circular lesion depending on the energy level and thelength of time of the ablation, and by rotating the catheter one or moretimes between delivery of ablation energy to electrodes 114. Asillustrated in FIG. 12, the distal portion 117 of the distal shaftsection is positioned within the pulmonary vein 41, to allow for mappingand/or pacing from within the pulmonary vein. Thus, the sensingelectrodes allow for sensing electrical activity before and after theablation energy is delivered to electrodes 114, to determine theappropriate location of the device, and whether the lesions formedtherefrom sufficiently treated the atrial arrhythmia. Although notillustrated, in one embodiment of performing a medical procedure, thehelically shaped proximal portion 116, and the distal portion 117 of theEP device 110 are both positioned within the pulmonary vein 41, similarto the embodiment illustrated in FIGS. 8 and 9.

FIG. 13 illustrates an alternative embodiment of an EP device 140embodying features of the invention, similar to catheter 110 but withhelical proximal portion 116 forming one full 360° loop and one quarterof a second loop, and with no electrodes 119 on the noncoiled distalportion 117. A presently preferred method of using EP device 140comprises positioning the helical proximal portion 116 just outside apulmonary vein at the ostium thereof, with the noncoiled distal portion117 used as an anchoring section within and in contact with thepulmonary vein. The helical proximal portion 116 is pushed against theatrial tissue just outside the pulmonary vein ostium, thereby ensuringgood contact with atrial tissue for ablation purposes. Pushing the shaftdistally with the helically shaped section braced against the atrialtissue thus collapses the helix and may advance a distal section of theproximal shaft section proximal to the helically shaped distal portionand through the ostium. The electrodes on the helical proximal portion116 are used to map for pulmonary vein potentials and only adiscontinuous, segmental lesion, rather than an entire circumference,continuous lesion, is formed by RF ablation, to barricade the pulmonaryvein potentials from exiting the pulmonary vein.

In one method of the invention, the lesion comprises one or more closedcircles on the endocardium. However, the lesion may alternativelycomprise a discontinuous, partially open circle formed by a plurality ofsmaller lesions. Additionally, the lesion may be formed by the helicaldistal shaft section in the noncollapsed configuration to extendhelically along a length of the body lumen, or the lesion may be formedby the helical distal shaft section in the collapsed configuration toextend only around the circumference of the body lumen and not helicallyalong a length of the body lumen. Typically, the lesion formed with theEP device 10/110/140 of the present invention has a width of about 2 toabout 7 mm, preferably about 3 to about 4 mm. The circumference of thelesion (forming a continuous closed circle, or a discontinuous partiallyopen circle) is about 5 to about 40 mm, preferably about 5 to about 20mm. A lesion extending only circumferentially around the body lumen andnot helically along a length of the body lumen (forming either acontinuous closed circle, or a discontinuous partially open circle) hasa length of about the thickness of the EP device shaft. A helical lesionextending helically along a length of the body lumen has a length ofabout to about 5 mm to about 50 mm, preferably about 5 to about 10 mm.Preferably, in the embodiment in which a plurality of continuous, closedcircle lesions are formed on the body lumen wall, the lesions are formednear the transition zone between the left atrial tissue and thepulmonary vein tissue.

The EP device 10/110/140 has a total length, including the connector 16,of about 100 cm to about 200 cm, and preferably between 150 and 180,e.g. about 165 cm. The length of the distal shaft section 13/113 havingelectrodes 14/114 is about 2 cm to about 15 cm, and preferably about 4to about 8 cm, e.g. about 6 cm. The outer diameter of the distal shaftsection of the device is typically about 1.0 mm (3.0 French) to about2.0 mm (6.0 French), and preferably about 1.3 mm (4 French) to about 1.7mm (5 French). The maximum outer dimensions of the electrodes aregenerally about 1.0 mm (3 Fr) to about 1.3 mm (4 Fr), and preferablyabout 1.22 mm (3.7 Fr). The electrode length is about 2 mm to about 8mm, and preferably about 4 to about 7 mm, e.g. about 6 mm. Theinterelectrode spacing is generally about 1 mm to about 3 mm, andpreferably about 2 mm. In a presently preferred embodiment, theinterelectrode spacing is uniform. However, the electrode spacing mayalternatively be nonuniform. In a presently preferred embodiment, about4 to about 12 individual electrodes are provided on the shaft distalsection, however, the device may have larger number of electrodes if thediameter of the distal section is increased to greater than 5 Fr.

Typically, the device is used within the patient's vasculature, althoughit may also be used to create lesions within other body lumens. Thedevice may be advanced retrogradely through the aorta and left ventriclevia a femoral artery access site. As illustrated in FIG. 8, the guidingcatheter may have a bent or deflectable distal end. Torquing theproximal section 22 of the guiding catheter, which extends out of thepatient during the procedure, will cause the distal section thereof tobe rotatably displaced within the body lumen and allow the EP device 10to be properly positioned.

To the extent not already discussed herein, the EP device components canbe formed of conventional materials. The core member 17/123 can beformed of a variety of suitable materials including high spring-backmetals, or superelastic metals, or shape memory metals, such as ELGILOYavailable from Carpenter Technology of Pennsylvania, MP35N, availablefrom SPS Technologies, high tensile strength steel including 304vacuum-melted steel, and titanium alloys including Ti-GAI-4V, C_(p)Titanium, and NiTi.

The electrical connector 14 on the proximal end of the device may be acommercially available electrical connector such as Part No.PAB-M08-GLA39J or PAB-M08-TLA39J for an eight pin connector or Part No.PAB-M08-GLA39A for a connector with a greater number of pins, e.g. 9-16.The above connectors are available from Lemo USA, Inc. in Santa Rosa,Calif. Suitable connectors for accessory cables connectable to the aboveconnectors include PRB-M08-GLL65J for eight pin connectors andPRB-M08-GII65A for connectors with more than eight pins. The latterconnectors are also available from the same source.

While the invention has been described herein in terms of certainpreferred embodiments directed to the detection and treatment of atrialfibrillation and flutter, those skilled in the art will recognize thatthe invention may be employed in a wide variety of procedures. A varietyof modifications and improvements may be made to the present inventionwithout departing from the scope thereof. Moreover, although individualfeatures of embodiments of the invention may be shown or discussed inrelation to some of the embodiments and not in others, those skilled inthe art will recognize that individual features of one embodiment of theinvention can be combined with any or all the features of anotherembodiment.

1. An electrophysiology device for ablating tissue in a patient's body,comprising: a) an elongated shaft having a proximal end, a distal end,and a distal shaft section with a helically shaped proximal portionwhich has one or more turns and which has a longitudinal axis; and astraight distal portion which extends distally from the helically shapedproximal portion of the distal shaft section and which has alongitudinal axis parallel to and off-set from the longitudinal axis ofthe helically shaped proximal portion b) at least one ablation electrodeon the helically shaped proximal portion of the distal shaft section. 2.The device of claim 1 wherein the turns of the helically shaped proximalportion of the distal shaft section have a diameter substantially equalto or greater than a diameter of an ostium of a body lumen.
 3. Thedevice of claim 1 wherein the helically shaped proximal portion of thedistal shaft section has at least one and one quarter turns havingsubstantially equal diameters.
 4. The device of claim 1 wherein thedistal shaft section has a core member which extends through at least apart of the helically shaped proximal portion and at least part of thestraight portion.
 5. The device of claim 4 wherein the core member inthe distal section has a helical shape.
 6. The device of claim 4 whereinthe core member is formed at least in part of a NiTi alloy.
 7. Thedevice of claim 4 wherein the shaft has a lumen extending thereinconfigured to slidably receive the core member.
 8. The device of claim 1including a plurality of sensing and pacing electrodes on the distalshaft section.
 9. (Cancelled)
 10. (Cancelled)
 11. The device of claim 1wherein the straight distal portion has a flexible coiled tip extendingfrom the distal end thereof. 12.-15. (Cancelled)
 16. The device of claim1 wherein the straight distal portion has at least two sensingelectrodes.
 17. The device of claim 1 wherein the straight distalportion has at least two sensing.
 18. (Cancelled)
 19. The device ofclaim 1 wherein the straight distal portion has a length of about 2 toabout 8 cm.
 20. The device of claim 1 wherein the helical proximalportion has a length of about 0.5 to about 1 cm.
 21. The device of claim1 wherein the helical proximal portion has a circumference of about 5 toabout 40 mm.
 22. (Cancelled)
 23. A method of performing a medicalprocedure, comprising: a) providing an electrophysiology device,comprising an elongated shaft having a proximal end, a distal end, and adistal shaft section having a helically shaped proximal portion havingone or more turns and a straight distal portion; and at least oneablation electrode on the helically shaped proximal portion; and b)positioning at least part of the helically shaped proximal portion incontact with a wall defining an ostium of a patient's body lumen; and c)delivering high frequency energy to the at least one ablation electrodeto form a lesion,
 24. The method of claim 23 including after (b), movingthe turns of the helically shaped proximal portion closer together bydistally forcing the catheter against the wall defining the ostium. 25.The method of claim 23 wherein the ostium is a junction of a pulmonaryvein with a left atrium, and (c) comprises forming a plurality ofdiscontinuous lesions around the ostium.
 26. The method of claim 23wherein the ostium is a junction of a pulmonary vein with a left atrium,and the device has at least one sensing electrode on the distal portion,and wherein the pulmonary vein is mapped by sensing electrical activitywith the sensing electrode.
 27. The method of claim 23 whereindelivering high frequency energy to the at least one ablation electrodeforms a lesion extending at least in part around the ostium of the bodylumen.
 28. The method of claim 27 wherein the helically shaped proximalportion of the distal shaft section of the device Is placed In ajunction between a pulmonary vein and an atrium of a patient to form alesion to treat the patient for atrial arrhythmia.
 29. The method ofclaim 28 wherein the device has a plurality of electrodes on thehelically shaped proximal portion of the distal shaft section, andwherein a plurality of discontinuous lesions are formed at the junctionbetween the pulmonary vein and an atrium to treat the patient for atrialarrhythmia.
 30. (Cancelled)
 31. The method of claim 28 wherein thedevice has a plurality of electrodes on the helically shaped proximalportion of the distal shaft section, and including after (c), moving theturns of the helically shaped proximal portion closer together anddelivering high frequency energy to at least one electrode on thehelically shaped proximal portion to form a second lesion continuouswith the first lesion.
 32. The method of claim 28 wherein the helicallyshaped proximal portion has a plurality of ablation electrodes, and thestraight distal portion has at least one sensing electrode, and whereinthe pulmonary vein is mapped by the at least one sensing electrodesensing electrical activity.
 33. The device of claim 1 wherein thestraight distal portion has at least two pacing electrodes.
 34. Thedevice of claim 1, wherein the helically shaped proximal portion has alongitudinal axis coincident with the longitudinal axis of the elongatedshaft.
 35. The device of claim 1, wherein the straight distal portion ofthe distal shaft section has a core member which is at least in parttapered over a length thereof.
 36. The device of claim 1, wherein thestraight distal portion anchors the distal shaft section.
 37. The deviceof claim 1 wherein the core member is at least in part formed of amaterial selected from the group consisting of high spring-back metals,superelastic metals and shape-memory metals.
 38. The device of claim 37wherein the superelastic material is a NiTi alloy.
 39. Anelectrophysiology device for detecting electrical activity within apatients heart chamber, comprising: a. an elongated shaft having aproximal end, a distal end, and a distal shaft section which is at leastin part helically shaped with at least one turn and which has at leastone electrode for detecting electrical activity on the helically shapedportion of the distal shaft section and which has a longitudinal axis;and b. a straight distal portion which extends distally from thehelically shaped proximal portion of the distal shaft section and whichhas a longitudinal axis parallel to and off-set from the longitudinalaxis of the helically shaped proximal portion.
 40. The electrophysiologydevice of claim 39 wherein the at least one electrode is about 2 toabout 8 mm in length.
 41. An electrophysiology device for a procedurewithin a patient's heart chamber, comprising an elongated shaft whichhas a helically shaped distal shaft portion having a plurality of spacedapart electrodes and being configured to engage an ostia within thepatients heart chamber.
 42. The electrophysiology device of claim 40wherein the spacing between at least two adjacent electrodes is not morethan about 3 mm.
 43. The electrophysiology device of claim 40 whereinthe spacing between at least two adjacent electrodes is not less thanabout 1 mm.
 44. The electrophysiology device of claim 40 wherein thedistal shaft section has at least one temperature sensor.
 45. Theelectrophysiology device of claim 44 wherein the at least onetemperature sensor is disposed between two adjacent electrodes.
 46. Theelectrophysiology device of claim 40 wherein the helically shaped distalshaft portion has at least four electrodes.
 47. The electrophysiologydevice of claim 40 wherein the helically shaped distal shaft portion hasup to about 12 electrodes.
 48. The electrophysiology device of claim 40wherein a plurality of the electrodes are ablation electrodes.
 49. Theelectrophysiology device of claim 40 wherein a plurality of theelectrodes are sensing electrodes.
 50. The electrophysiology device ofclaim 40 wherein the elongated shaft has a straight distal shaft portionextending distally from the helically shaped distal shaft portion. 51.The electrophysiology device of claim 50 wherein the straight distalportion has a longitudinal axis parallel to and off-set from alongitudinal axis of the helically shaped distal shaft portion.
 52. Theelectrophysiology device of claim 40 wherein the helically shaped distalshaft portion has a core member.
 53. The electrophysiology device ofclaim 52 wherein the core member Is formed of a material selected fromthe group consisting of high spring-back metals, superelastIc metals andshape-memory metals.
 54. The electrophyslology device of claim 53wherein the superelastic material is a NiTi alloy.
 55. Theelectrophysiology device of claim 41 wherein at least one of the spacedapart electrodes is about 2 to about 8 mm in length.
 56. Anelectrophysiology device for a procedure within a patient's heartchamber, comprising an elongated shaft which has an expandable distalshaft portion having a plurality of spaced apart electrodes and beingconfigured to engage an ostia within the patients heart chamber.